[Mamaly]

Driving a brand new 2018 Outback Touring (my 4th Subaru) and today I learned the hard way that the "20-miles-left-until-empty" in the "driving range" indicator really means "get your rear in gear to a gas station NOW!" (Wish I had found this forum prior). Fortunately, I was at home and had some gasoline stored in the garage and was able to fill-up enough to get me to the local gas station.

As I restarted the car and drove away from the house, the "driving range" number (which had been at 20 miles) appeared to reset to "---.--"

I drove about 2 miles to a gas station. According to the gas pump, I filled the tank with 17.66 gallons of gas. When I restarted the car, the "driving range" number reset to 300.

Odd, I thought. That seems really low. At an average of 23 miles per gallon and a 18.5 gallon tank, I should see 425 miles in the "driving range". In fact, the last time I filled the tank up, I am pretty sure that the "driving range" number appeared as roughly 400 or 425. (As a side note, my MPG was averaging about 23.4, since I've mostly only done city/suburb driving, since I got the car a couple of weeks ago.)

Over the course of the next few hours, I drove a total of 30 miles (almost exactly). However, the "driving range" number is still reading 300. It didn't move at all.

Wondering if anyone has encountered this problem. I have to take the car to the dealer in the next day or so to get the gas hatch door looked at, and can ask about it at this time. (The gas hatch isn't opening when the lever is pulled and I need a 2nd person to get their fingernails under the hatch when I pull the lever - which is why I had delayed in filling the gas tank up in the first place, but I digress...)

Appreciate thoughts.

 

[ammcinnis]

Wondering if anyone has encountered this problem.

There is no problem. Your system appears to be working as designed. The Distance to Empty estimate is based on recent fuel economy. It's not at all unusual for DTE to actually go up (temporarily) as you drive in varying conditions.

 

[atc98092]

I wouldn't call it a problem (although the issue with the inaccurate miles left has been discussed in detail in another thread). But I wouldn't be concerned with it sitting at 300. Remember that DTE uses an algorithm that uses recent driving (I don't know how long) to estimate the MPG for the remaining fuel. If you had been doing slow, in-town driving before you ran out at home, that distance is most likely being calculated at less than 20 MPG. If you are now driving under conditions that would increase that MPG, for example now doing some smooth freeway driving, it is continually moving that MPG bar higher, so even though you are driving quite a distance, the DTE remains the same.

I see that often. I live on a pretty good hill, so when I gas up I have to climb quite a bit to get home. From the station to my house I probably don't average over 15 MPG. But the next morning when I leave for work, I first have the downhill run, then an almost non-stop until the freeway. In fact, many mornings I go from the stop sign at the bottom of my hill into my work parking lot without stopping, and that's 17 miles. I often see the DTE actually increase. In my diesel Passat that I had before my OB, I could see the DTE increase by more than 50 miles on my drive to work. Of course, I was getting 50 MPG on that drive, so it changed a bit faster!

 

[ncdave]

While the estimated remaining range is systematically off, it should be moving around. If it's stuck at 300 for a substantial number of miles, there may be some problem. Is your gas gauge tracking properly (although at only 30 miles, it won't have moved much regardless)?

 

[phishfood]

I would give it a tank and a fill up before worrying.

Have you reset your trip counters?

I ran out of gas on side of road with "XX miles to empty" while I was on a trip. Usually I am one to fill when I see it a little under half a tank but when I'm driving 2000 miles I don't want to be stopping every 3.5 hours for gas.

Know better now lol

 

[skipw]

While the estimated remaining range is systematically off, it should be moving around. If it's stuck at 300 for a substantial number of miles, there may be some problem. Is your gas gauge tracking properly (although at only 30 miles, it won't have moved much regardless)?

Since it changes in 10-mile increments, it can easily stay at 300 miles for 30 miles or longer if your recent fuel economy (not the number shown on the display) improved. Going from, say, 25 mi/gal with 12 gallons remaining to 27 mi/gal with 11 gallons remaining after a 30 mile stretch at 30 mi/gal will produce that result and isn't difficult to envision. If your recent mileage increases dramatically in a situation like going from uphill stop-and-go traffic to open road with a tailwind, the estimated remaining range will likely increase, sometimes a lot!

 

[ammcinnis]

... in a situation like going from uphill stop-and-go traffic to open road with a tailwind, the estimated remaining range will likely increase, sometimes a lot!

I once saw (briefly) a DTE display of almost 800 miles in our 2015 Legacy. This was immediately after filling the tank (in Cameron, AZ) following a long, moderate speed, high-elevation, downhill run from the north rim of the Grand Canyon, with a slight tailwind, and during which the fuel computer had been reporting better than 44 mpg. After a few miles of driving following the fuel stop, DTE soon returned to a more rational figure.

 

[JRobyn]

2018s seem to almost ALL run totally dry just as they hit "30 Mi Range" based on feedback in various places in this forum. And the second that the fuel indicator needle is fully over the "E" mark, you are OUT!

 

[BubbaATL]

I didn't realize until this past weekend that it only changes in 10-mile increments. I thought it was stuck at 50 miles, and I got kinda scared because I was stuck myself in terrible traffic on a road where I had run out of gas exactly that way some years ago in another vehicle.

Then it finally dropped to 40 and I thought "whew," but still got off at the next exit.

Another thing - I'm not sure I've noticed it in this car, but in other vehicles I've occasionally seen the miles-to-empty indicator go UP rather than down, as it recalculates based on current driving conditions.

 

[Rub]

Your car has fuzzy logic and the estimated range seems to be based on how the car was driving on the previous tank and the driving conditions.

The weird looking display is normal and I see it all the time when I do a lot of pure city driving right before I fill up. OTOH, if I'm doing pure highway driving on say a road trip, the display will say 460.

Don't try to understand the fuzzy logic but accept that it's there.

 

[Shadow5501]

I've seen different behaviors of the MTE functionality across different vehicle manufacturers. Mercedes is generally very accurate. When they first inteoduced the function, it would show range to the nearest tenth of a mile when the car was near empty. Somewhere I have a photo of my old E320 showing 0.4 miles to empty. Made it to the fuel station though. MB will spin the range number up and down by a large amount while it is displayed. Climb a mile long hill and it might reduce by 50 miles, coast down the other side and it will spin back up.

I currently have a Ford Focus ST. It never increases the MTE number unless you add fuel to the car. Instead, it appears to decrease the rate at which the displayed MTE number is reduced until the display and the currently calculated range equalize. There are a few complaints that folks ran out of fuel on the ST forum, but fewer than seem to occur here.

Honda would increase the MTE number while driving, but not while it was displayed. You had to switch the display to another value, then come back to MTE and magically your range had increased!

It's all just a software algorithm, backed up by the accuracy of the electro-mechanical fuel sending unit. In my experience the MB worked the best, it was very accurate. If it said you had fuel and range, you had fuel and range. Unfortunately, Subaru is the worst I have yet seen. Counting down to 30 and then switching to dashes (on my '16) renders it pretty much useless in my opinion. I have learned from y'all (thanks!) to be more diligent about refueling the Subie, as they seem more prone to running out of fuel than other makes & models of vehicle I have owned.

 

[theoak]

'18 Touring "Driving Range" Fuel Appears Stuck

I thought my brand new ‘18 started at 300 also. It now floats its initial guess from 500 to 540 based on some math.


Sent from my iPhone using Tapatalk

 

[skipw]

I've seen different behaviors of the MTE functionality across different vehicle manufacturers. Mercedes is generally very accurate. When they first inteoduced the function, it would show range to the nearest tenth of a mile when the car was near empty. Somewhere I have a photo of my old E320 showing 0.4 miles to empty. Made it to the fuel station though.

The real test of accuracy is if it sputters and dies the moment the estimate hits zero. Someone reported in a different thread that his VW would go another 70 miles after hitting zero. In that case, seeing a number greater than zero may be reassuring, but it's not accurate. When it's showing zero, the question becomes "how long ago did that happen?"

I currently have a Ford Focus ST. It never increases the MTE number unless you add fuel to the car. Instead, it appears to decrease the rate at which the displayed MTE number is reduced until the display and the currently calculated range equalize. There are a few complaints that folks ran out of fuel on the ST forum, but fewer than seem to occur here.

That's an interesting approach, but I don't see how that strategy would make it more likely to run out of fuel since the distance shown would be either the current estimate or less. The estimate may be optimistic, but that is a different issue.

Subaru is the worst I have yet seen. Counting down to 30 and then switching to dashes (on my '16) renders it pretty much useless in my opinion.

Useless? Why?

I like this better than a display that goes to zero with 70 miles of usable range left. Just Fill it before it gets to 30 and you'll be fine. Lower than 30, you can't count on scavenging all of the small amount of fuel remaining in the tank and you're at risk of getting stranded.

I have learned from y'all (thanks!) to be more diligent about refueling the Subie, as they seem more prone to running out of fuel than other makes & models of vehicle I have owned.

I find the number of drivers who push the envelope in an unfamiliar car simply astonishing. In my case, I didn't rely on that number until I knew what it meant, but maybe I'm more analytical than most. Based on amounts needed to refill the 18.5-gallon tank, zero estimated range means the tank would be dry, which is fine since I realize it's not prudent to count on being able to use every bit of those last few pints.

 

[Shadow5501]

The real test of accuracy is if it sputters and dies the moment the estimate hits zero. Someone reported in a different thread that his VW would go another 70 miles after hitting zero. In that case, seeing a number greater than zero may be reassuring, but it's not accurate. When it's showing zero, the question becomes "how long ago did that happen?"



That's an interesting approach, but I don't see how that strategy would make it more likely to run out of fuel since the distance shown would be either the current estimate or less. The estimate may be optimistic, but that is a different issue.



Useless? Why?

I like this better than a display that goes to zero with 70 miles of usable range left. Just Fill it before it gets to 30 and you'll be fine. Lower than 30, you can't count on scavenging all of the small amount of fuel remaining in the tank and you're at risk of getting stranded.



I find the number of drivers who push the envelope in an unfamiliar car simply astonishing. In my case, I didn't rely on that number until I knew what it meant, but maybe I'm more analytical than most. Based on amounts needed to refill the 18.5-gallon tank, zero estimated range means the tank would be dry, which is fine since I realize it's not prudent to count on being able to use every bit of those last few pints.

The Mercedes required the rated tank volume to fill when it showed ~0 range, so I would say it was both precise and accurate.

The MTE display is just a calculation of remaining fuel vs rate of use. Measuring the remaining fuel accurately would be of paramount importance. The inexpensive Ford seems to have some lack of accuracy, hence the reason people occasionally run out. The OB seems to have errors of up to approx 2 gallons, based on the MTE values quoted by folks that have run out of fuel. The reason I find the Subaru implementation frustrating is because MTE is more interesting and important the smaller the value. I don't plan my fuel and rest stops from 500 miles out, but at 50 or 100 it becomes rather more interesting. That said, my OB is reasonably accurate - when the fuel level reads empty, it takes quite close to the 18.5 gallon capacity to fill the tank.

 

[JRobyn]

Our '15 Forester was EXTREMELY accurate and trustworthy, so Subaru is capable of doing it. Perhaps the tank shape and sending unit placement is what's affecting this.

We sometimes intentionally "push the envelope" while nearing a COSTCO where we know there's good-quality and substantially lower $ fuel.

 

[skipw]

Our '15 Forester was EXTREMELY accurate and trustworthy, so Subaru is capable of doing it. Perhaps the tank shape and sending unit placement is what's affecting this.

We sometimes intentionally "push the envelope" while nearing a COSTCO where we know there's good-quality and substantially lower $ fuel.

Sure, but it sounds like you're already familiar with the system and know it's accurte. Nothing wrong with that; I do it occasionally, too - I'll wait until it shows --- every now and then, but not often, and only when I know I can fill up almost immediately.

What really gets me is people when complain after they run out of gas on the first tank.

 

[skipw]

The Mercedes required the rated tank volume to fill when it showed ~0 range, so I would say it was both precise and accurate.

The MTE display is just a calculation of remaining fuel vs rate of use. Measuring the remaining fuel accurately would be of paramount importance.

Sounds like it's accurate then.

I posted this a couple of months ago.

It seems like the Outback's measurement is accurate in terms of remaining fuel volume. The hack on the Y-axis of the chart at 18.433 gallons to fill is where the linear regression intercepts the Y-axis (0 miles to empty). What may be causing people trouble is the fact that they can't use the last little bit of fuel. This isn't surprising since how much of it can be reached will depend, among other things, on the attitude (pitch and roll) of the vehicle.

The inexpensive Ford seems to have some lack of accuracy, hence the reason people occasionally run out. The OB seems to have errors of up to approx 2 gallons, based on the MTE values quoted by folks that have run out of fuel.

As you can see from the chart, there have been 8 or more fill-ups of 17 gallons or more, meaning less than 1.5 gallons remaining. Largest was 17.444 gallons, meaning there was almost exactly 1 gallon left. Two gallons seems like an overstatement, but, as is often repeated, "YMMV".

The reason I find the Subaru implementation frustrating is because MTE is more interesting and important the smaller the value. I don't plan my fuel and rest stops from 500 miles out, but at 50 or 100 it becomes rather more interesting. That said, my OB is reasonably accurate - when the fuel level reads empty, it takes quite close to the 18.5 gallon capacity to fill the tank.

There's no need to plan 500 miles out, and estimates in that range are subject to way too many variables to be relied on to any degree. Depending on where you are, when it hits 100 you should at least be thinking about it (sooner if it's sparsely populated, like most of Nevada - in that case, getting much below half a tank is poor planning). At 50, it's really time for me unless I'm in or near an area where I know there will be a lot of opportunities to refuel.